Silicon-nanowire field-effect transistors on a flexible substrate using top-down MEMS processes

Owing to their excellent flexibility and electrical characteristics, silicon-nanowire field-effect transistors (SiNW FETs) have been assessed for uses in flexible electronics. However, conventional fabrication processes are expensive or do not reliably reproduce device characteristics. This paper presents a novel SiNW FET fabrication technology for flexible electronics by using top-down MEMS processes. The SiNWs are fabricated in the <110> direction on a p-type (100) silicon wafer. Device electrodes are formed on bulk silicon to fabricate FET structures on a rigid substrate. The electrical characteristics of the devices are tested before and after transfer to a flexible polydimethylsiloxane film. When the gate voltage is −5 V with respect to source voltage, the SiNW FET has on-currents of approximately 54.1 and 52.9 μA before and after the transfer, respectively. Bending experiments show that the device exhibits excellent mechanical durability, indicating exciting new applications of microelectromechanical systems for flexible and wearable electronics.